Aluminum soaps



United States Patent ALUMINUM SOAPS Scott Mason, Stonington, Conn., and Herman B. Goldstein, Cranston, and Joseph F. Cotter, Providence, R. I., assignors to Sun Chemical Corporation, Long Island City, N. Y., a corporation of Delaware No Drawing. Application July 9, 1953, Serial No. 367,074

8 Claims. (Cl. 260-414) The present invention relates to aluminum soaps, and more particularly to aluminum soaps especially adapted for bodying or gelling liquid hydrocarbon materials without the application of heat,

Aluminum soaps such as aluminum stearate, aluminum naphthenate, etc., have found use as bodying agents and as gelling agents for liquid hydrocarbon materials, waxes,

- oils, non-polar solvents, and for many commercial compositions in which such materials are employed, as, for example, surface coatings. However, the conventional aluminum soaps are often characterized by certain deficiences either in their physical or chemical properties, or in their use, whereby such soaps are rendered either unfit or undesirable for use as bodying agents or as gelling agents in many commercial applications. For example, a certain amount of heating is usually required to effect gelation of liquid hydrocarbon compositions with the conventional aluminum soaps. Such heating, however, often has an adverse effect upon the composition undergoing such treatment. Further, gels which have been formed with the conventional aluminum soaps usually exhibit poor stability in the presence of limited amounts of such gel breakers as water, free fatty acids, etc., and thus have a tendency to break when even small amounts of these materials are present. Some aluminum soaps, such as aluminum naphthenate, while good gelling agents for liquid hydrocarbon materials, are highly plastic and thus are difiicult to handle in normal commercial operations, While others in which the soap-forming acids consist in large measure of unsaturated fatty acids tend to be sticky and are susceptible to atmospheric oxidation.

By the present invention, however, there are provided aluminum soaps which are especially adapted as bodying and gelling agents for liquid hydrocarbon materials, which are dry free flowing granular powders, which are substantially non-susceptible to oxidation, which are capable of gelling aromatic and aliphatic liquid hydrocarbons, oils, waxes, etc., at room temperatures, that is approximately 70 F., by mere agitation of the aluminum soap-containing liquids for relatively short periods of time, which are capable of forming gels having improved stability and resistance toward breakdown in the .presence of limited amounts of materials which have a tendency to cause breakage of hydrocarbon gels, and which are more highly economical on a weight basis in the formation of gels with liquid hydrocarbon materials than are the conventional aluminum soaps.

The aluminum soaps of the present invention are aluminum soaps of a plurality of soap-forming acids, said soap-forming acids consisting of (l) a saturated higher fatty acid material having at least 16 carbon atoms, (2) lauric acid, or fatty acids of the vegetable oils in which the predominant fatty acid is lauric acid, and (3) 2-ethyl hexoic acid.

The saturated higher fatty acid material which is employed as one of the component soap-forming acids in the preparation of the aluminum soaps of the present 2,758,123 Patented Aug. 7, 1956 invention maybe of any of the saturated fatty acids having .at least 16 carbon atoms, such as palmitic acid, stearic acid, arachi-dic acid, behenic acid, etc. There may also be utilized fatty acid compositions which consist essentially of a mixture of saturated higher fatty acids of-at least 16 carbon atoms as, for example, hydrogenated fish oil fatty acids, hydrogenated tallow fatty acids, and in general any hydrogenated animal or vegetable oils which consist essentially of fatty acids having at least 16 carbon atoms.

The second of the soap-forming fatty acid components may be lauric acid, or it may consist of the fatty acids of naturally-occurring vegetable oils in which the predominant fatty acid is lauric acid as, for example, coconut fatty acids, the fatty acids of palm-kernel oil, and thefatty acids of babassu oil.

The third of the soap-forming fatty acid components employed in preparing the aluminum soaps of the present invention is a saturated fatty acid of 8 carbonatoms; specifically, 2-ethyl hexoic acid.

To obtain aluminum soaps having the specific properties and characteristics of those herein described, it is essential that the various soap-forming fatty acids be employed Within certain definite proportions with respect to each other. For example, the saturated higher fatty acid material of at least 16 carbon atoms should constitute from approximately 10% to approximately 40% by weight of the total amount of the soap-forming acids. The presence of this material in such amounts insures the provision of an aluminum soap of sufilciently high melting point and hardness such that the end product, when ground or pulverized, is a. dry free-flowing powder. The second of the soap-forming components utilized in preparing the aluminum soaps of the present invention, that is, the fatty acid material in which the predominant fatty acid is lauric acid, should constitute from approximately 20% to approximately 60% by weight of the total amount of the soap-forming acids. The presence of this material in the aluminum soaps in the amounts set forth insures easy solvation of the aluminum soap in liquid hydrocarbons and promotes low temperature gela' tion of such materials. The 2ethyl hexoic acid-should also be utilized in an amount of from approximately 20% to approximately 60% by weight of the total amount of the soap-forming acids. When used in such-amounts, in combination with the remaining soap-forming acids, the 2-ethyl hexoic acid imparts the properties of increased gel stability and gel strength to gels of the liquid hydrocarbons prepared with the aluminum soaps of the present invention, and is also believed to be responsiblefor the excellent economy of usage which is obtained with these soaps.

The following examples illustrate aluminum soaps of the present invention and the manner in which these soaps are prepared.

Example 1 Lbs. Hydrogenated fish oil fatty acids .6.0 Coconut fatty acids 12.0 2-ethyl hexoic acid 12.0 Caustic soda (50% aqueous solution) 20.0 Aluminum sulfate-18Hz0 31.0

The method of preparing the aluminum soap compositions of the present invention consists in simultaneously coprecipitating the aluminum soaps of a mixture of the fatty acids. Thus, in preparing an aluminum soap composition with the materials set forth above, the hydrogenated fish oil fatty acids, the coconut fatty acids, and the 2-ethyl hexoic acid, in the amounts shown .are added to '25 gallons of water at 70 C. and are then saponified by the addition of 20 lbs. of a 50% aqueous Solution of causticsoda. 50 gallons of cold water are then added to the soap solution and the temperature is adjusted to approximately 40 C. A solution of the aluminum sulfate dissolved in 10 gallons of water at 65 "-70" C. is then slowly added to the solution of the sodium soaps with agitation to efiect precipitation of the aluminum soaps of the fatty acids. When the addition of the aluminum sulfate solution has been completed, the entire batch is agitated for about 15 minutes and then allowed to rest for about 30 minutes without agitation. The water is then drawn on, cold water in an amount equal to that which was drawn off is added to the batch, and the temperature is again adjusted to approximately 40 C. The slurry thus formed is agitated for about 15 minutes, allowed to stand undisturbed for about 20 minutes, and the water is again drawn oif. This process is repeated until a total of 6 draw-offs of water has been eflFected, and the product thus obtained is then filtered, washed, dried, and pulverized. The end product is a dry, free-flowing powder which is capable of use for gelling liquid hydrocarbon materials and the like without the application of heat. For example, parts by weight of the aluminum soap obtained in accordance with Example 1, when added to 95 parts by weight of mineral spirits, converted the mineral spirits into a heavy gel after 3 minutes stirring at a temperature of 70 F. Similarly, 5 grams of the aluminum soap of Example 1, added to 95 grams of Napalm solvent in a 9-ounce sealed jar, formed a rigid gel of the said solvent after rolling the jar for 2 minutes at a temperature of 70 F. In both cases the gels which were formed were stable during storage.

The alumina content of the soaps of the present invention, calculated on the ratio of mols of caustic soda to mols of fatty acid, may be varied within the range of approximately l.32.3, and is preferably maintained within the range of approximately l.4l.7. The alumina content of the said soaps is determined by the amount of caustic soda employed rather than by the amount of aluminum sulfate since an excess of aluminum sulfate over the amount of caustic soda is always utilized to effect formation of the aluminum soaps. If the alumina content of the soaps, based on the ratio of mols of caustic soda to mols of fatty acids, is substantially less than 1.3, the aluminum soap is generally too sticky and too plastic for satisfactory use in accordance with the present invention. If a ratio greater than approximately 2.3 is utilized, the rate of solvation and gelation of the soap-solvent mixes is generally too slow and unsatisfactory for commercial applications.

Further examples of formulations satisfactorily employed in the preparation of the aluminum soaps of the present invention are as follows. The procedure set forth in Example 1 for the preparation of the aluminum soap is followed with respect to the formulations shown in the following examples.

Example 2 Lbs.

Hydrogenated tallow fatty acids 6.0 Coconut fatty acids 6.0 Z-ethyl hexoic acid 18.0 Caustic soda (50% aqueous solution) 31.8 Aluminum sulfate-l8I-Iz0 48.5

Example 3 Lbs.

Stearic acid 6.0 Laurie acid 6.0 2-ethyl hexoic acid 18.0 Caustic soda (50% aqueous solution) 21.0 Aluminum sulfate-ISHzO 32.0

Example 4 Lbs. Hydrogenated tallow fatty acids 6.0 Coconut fatty acids 12.0 Z-ethyl hexoic acid 12.0 Caustic soda (50% aqueous solution) 20.5 Aluminum sulfate-18Hz0 28.5

Example 5 Lbs.

Stearic acid 12.0 Coconut fatty acids 8.0 2ethyl hexoic acid 10.0 Caustic soda (50% aqueous solution) 15.4 Aluminum sulfate-l8I-I2O 23.4

The aluminum soaps of the present invention, as exemplified by the above illustrative formulations, have been found to be of value for the gelation without the application of heat of many monomeric and polymeric hydrocarbons such as mineral spirits and naphthas, coal tar solvents, benzene, toluene, xylene, styrene, gasoline, kerosene, chlorinated hydrocarbons, polybutenes and polyethylenes. These soaps are of particular value for forming gels in the cold in such applications when the application of heat constitutes a fire hazard. Further applications in which the soaps are of utility are in the manufacture of surface coatings, pigment dispersions, rubber cements, paint removers, and bodied oils and polymers. For example, the soaps may be used to increase the viscosity of paint batches which have been manufactured at undesirably low viscosities.

Gels formed with the new aluminum soaps display improved stability over gels made with conventional stearates toward breakdown caused by such gel breakers as water, free fatty acids, and traces of mercaptans, amines and sulfonates. It has also been found that the new aluminum soaps are generally 3 to 4 times as economical on a weight basis in the formation of gels than are conventional aluminum stearates, and are sometimes more than times as economical on the same basis. Since any unsaturated acids which may be present in some of the soap-forming acids used in the present invention are present in, at most, only limited amounts, the aluminum soaps are substantially non-susceptible to atmospheric oxidation or to atmospheric oxidation or to the develop ment of stickiness in storage. Thus, no appreciable physical or chemical changes occur in the soaps under normal storage conditions which might possible adversely modify the properties of these soaps with respect to their utility or with respect to the manner and ease with which these materials may be handled and employed in commercial operation.

While the above described products and processes constitute preferred embodiments of the present invention, changes may be made therein Without departing from the scope of the invention as defined in the appended claims.

What is claimed is:

1. An aluminum soap of a plurality of soap-forming acids, said acids consisting of approximately 1040% by weight of a material of the group consisting of the saturated higher fatty acids of at least 16 carbon atoms and mixtures thereof, approximately 2060% by weight of a material of the group consisting of lauric acid and fatty acids of the vegetable oils in which the predominant fatty acid is lauric acid, and approximately 20-'60% by weight of Z-ethyl hexoic acid, the alumina content of the final product being controlled by reacting 1.3 to 2.3 mols of sodium hydroxide with each mol of soap-forming acid present and the resulting sodium soaps being completely neutralized by an amount of aluminum sulfate slightly in excess of the stoichiometric amount.

2. An aluminum soap of a plurality of soap-forming acids, said acids consisting of approximately 10-40% by weight of stearic acid, approximately 20-60% by weight of lauric acid and approximately 2060% by weight of 2-ethyl hexoic acid, the alumina content of the final product being controlled by reacting 1.3 to 2.3 mols of sodium hydroxide with each mol of soapforming acid present and the resulting sodium soaps being completely neutralized by an amount of aluminum sulfate slightly in excess of the stoichiometric amount.

3. An aluminum soap of a plurality of soap-forming acids, said acids consisting of approximately l-40% by weight of hydrogenated tallow fatty acids, approximately 20-60% by weight of a material of the group consisting of lauric acid and fatty acids of the vegetable oils in which the predominant fatty acid is lauric acid, and approximately 2060% by Weight of 2-ethyl hexoic acid, the altunina content of the final product being controlled by reacting 1.3 to 2.3 mols of sodium hydroxide with each mol of soap-forming acid present and the resulting sodium soaps being completely neutralized by an amount of aluminum sulfate slightly in excess of the stoichiometric amount.

4. An aluminum soap of a plurality of soap-forming acids, said acids consisting of approximately 40% by weight of hydrogenated fish oil fatty acids, approximately 20-60% by weight of a material of the group consisting of lauric acid and fatty acids of the vegetable oils in which the predominant fatty acid is lauric acid, and approximately 20-60% by weight of 2-ethyl hexoic acid, the alumina content of the final product being controlled by reacting 1.3 to 2.3 mols of sodium hydroxide with each mol of soap-forming acid present and the resulting sodium soaps being completely neutralized by an amount of aluminum sulfate slightly in excess of the stoichiometric amount.

5. An aluminum soap, of a plurality of soap-forming acids, said acids consisting of approximately 1040% by weight of a material of the group consisting of the saturated higher fatty acids of at least 16 carbon atoms and mixtures thereof, approximately 2060% by weight of lauric acid, and approximately 20-60% by weight of 2-ethyl hexoic acid, the alumina content of the final product being controlled by reacting 1.3 to 2.3 mols of sodium hydroxide with each mol of soap-forming acid present and the resulting sodium soaps being completely neutralized by an amount of aluminum sulfate slightly in excess of the stoichiometric amount.

6. An aluminum soap of a plurality of soap-forming acids, said acids consisting of approximately 10-40% by weight of a material of the group consisting of the saturated higher fatty acids of at least 16 carbon atoms and mixtures thereof, approximately 2060% by weight of coconut fatty acids, and approximately 20-"60% by weight of 2-ethyl hexoic acid, the alumina content of the final product being controlled by reacting 1.3 to 2.3 mols of sodium hydroxide with each mol of soap-forming acid present and the resulting sodium soaps being completely neutralized by an amount of aluminum sulfate slightly in excess of the stoichiometric amount.

7. An aluminum soap of a plurality of soap-forming acids, said acids consisting of approximately 10-40% by weight of hydrogenated fish oil fatty acids, approximately 2060% by weight of coconut fatty acids, and approximately 20-60% by weight of 2-ethyl hexoic acid, the alumina content of the final product being controlled by reacting 1.3 to 2.3 mols of sodium hydroxide with each mol of soap-forming acid present and the resulting sodium soaps being completely neutralized by an amount of aluminum sulfate slightly in excess of the stoichiometric amount.

8. An aluminum soap of a plurality of soap-forming acids, said acids consisting of approximately 1040% by weight of hydrogenated tallow fatty acids, approximately 2060% by weight of coconut fatty acids, and approximately 20-60% by weight of Z-ethyl hexoic acid, the alumina content of the final product being controlled by reacting 1.3 to 2.3 mols of sodium hydroxide with each mol of soap-forming acid present and the resulting sodium soaps being completely neutralized by an amount of aluminum sulfate slightly in excess of the stoichiometric amount.

References Cited in the file of this patent UNITED STATES PATENTS 1,990,320 Fulweiler et a1 Feb. 5, 1935 2,390,609 Minich Dec. 11, 1945 2,599,553 Hotten June 10, 1952 2,618,536 Hunn Nov. 18, 1952 2,626,897 Young et a1 J an. 27, 1953 2,628,202 Allison et al. Feb. 10, 1953 2,718,462 Cohen Sept. 20, 1955 

1. AN ALUMINUM SOAP OF A PLURALITY OF SOAP-FORMING ACIDS, SAID ACIDS CONSISTING OF APPROXIMATELY 10-40% BY WEIGHT OF A MATERIAL OF THE GROUP CONSISTING OF THE SATURATED HIGHER FATTY ACIDS OF AT LEAST 16 CARBON ATOMS AND MIXTURES THEREOF, APPROXIMATELY 20-60% BY WEIGHT OF A MATERIAL OF THE GROUP CONSISTING OF LAURIC ACID AND FATTY ACIDS OF THE VEGETABLE OILS IN WHICH THE PREDOMINANT FATTY ACID IS LAURIC ACID, AND APPROXIMATELY 20-60% BY WEIGHT OF 2-ETHYL HEXOIC ACID, THE ALUMINA CONTENT OF THE FINAL PRODUCT BEING CONTROLLED BY REACTING 1.3 TO 2.3 MOLS OF SODIUM HYDROXIDE WITH EACH MOL OF SOAP-FORMING ACID PRESENT AND THE RESULTING SODIUM SOAPS BEING COMPLETELY NEUTRALIZED BY AN AMOUNT OF ALUMINUM SULFATE SLIGHTLY IN EXCESS OF THE STOICHIOMETRIC AMOUNT. 